Final answer:
The Central Limit Theorem is used to find the mean and standard deviation of the sample means for samples of a given size from a population with a known mean and standard deviation.
Step-by-step explanation:
To find the mean μx and standard deviation σ¯x for samples of size n=25 from a population with a mean μ=18 and standard deviation σ=6, we will use the Central Limit Theorem. This theorem states that the sampling distribution of the sample mean will be normally distributed if the sample size is large enough (typically n>30, but smaller sizes can be used if the population distribution is already normal, which we will assume for this calculation).